Method of detection in an alarm system

ABSTRACT

An improved ionization detection method and apparatus is described wherein a material which is adapted to emit a vapor, aerosol or fumes at a predetermined elevated temperature is deposited on a body whose temperature is to be monitored. Means including an ionization detector are provided for sensing the emission and for indicating the existence of the predetermined body temperature.

United States Patent 1191 Langeron [4 1 Nov. 20, 1973 METHOD OFDETECTION IN AN ALARM 1,998,943 4/1935 Sabbah 328/3 SYSTEM 2,932,9714/1960 Moore et a1. 340/227 2,331,025 10/1943 Grooms 328/3 Inventor:Roger Jules Langeren, Avenue 3,329,022 7/1967 Feldman 73/358 deBretteville, Neuilly-sur-Seine, 3,520,274 7/1970 Schreier et a1116/114.5 France Primary Examiner-Harold A. Dixon [22] Flled' 1972Att0rneyWil1iam Kaufman et a1. [21] Appl. No.: 223,073

[57] ABSTRACT 52 US. Cl. 250/389, 340/227 s, 73/358 An improvedionization detection method and pp [51] Int. Cl. G0lt 1/18 we isdescribed r n a mat ial which is adapted to [58] Field of Search 73/358;116/114.5; emit a p aerosol or fumes a a p rm l 340/228 S, 227 S;250/835 vated temperature is deposited on a body whose temperature is tobe monitored. Means including an ion- [56] Ref re Cit d ization detectorare provided for sensing the emission UNITED STATES PATENTS and forindicating the existence of the predetermined 1,774,961 9 1930 Buchholz340/228 s body temperature 2,759,174 8/1956 Brailsford 340/228 S 3Claims, 8 Drawing Figures 1 METHOD OF DETECTION IN AN ALARM SYSTEM Thisinvention relates to an improved method and apparatus for detecting afault condition in an apparatus or for detecting prdeterminedenvironmental conditions.

The invention relates more particularly to an improved method andapparatus for employing an ionization detector for sensing predeterminedconditions.

It is often desirable to provide means for automatically monitoring theoperating conditions of apparatus such as machinery or complexelectronic apparatus. A fault condition in the machinery or electronicapparatus can result in the generation of a relatively large amount ofheat and cause self destruction of the equipment. Further, it is alsodesirable to monitor the atmospheric environment of such areas such asstorage depots, factories and the like in order to sense abnormalenvironmental conditions. For example, it is desirable at times tomonitor environmental conditions for detecting the escape of gases orfumes from storage containers or for sensing smoke as an early firewarning.

The ionization detector has proven itself to be a useful tool in sensingfumes, gases and/or aerosols which result from the existence of theabnormal condition. However, the use of ionization detectors hasheretofore required the generation of a vapor which could be de tectedand this vapor was provided by an overheated element or by fireresulting in smoke. Consequently, at least some preliminary damage anddestruction was perfected by the fault condition or abnormal environment until such vapors were generated and sensed by the detector. Itwould, of course, be desirable to provide a detection system whichsensed the abnormal conditions or environment with an ionizationdetector while at the same time eliminated the damage or partialdestruction to apparatus or the environment which is to be protected.

Accordingly, it is an object of this invention to provide an improvedmethod and apparatus for ionization detection.

Another object of the invention is to provide an improved method andapparatus for ionization detection which avoids damage or destructionpreliminary to the generation of vapors which can be sensed.

Another object of the invention is to provide an improved method andapparatus for sensing and indicat ing an abnormal condition in a machineor other apparatus.

A further object of the invention is to provide an improved method andapparatus for sensing abnormal environmental conditions.

In accordance with the general features of the method and apparatus ofthis invention, a material is deposited on a body which is to bemonitored or is located in an atmosphere which is to be monitored. Thematerial comprises a vaporizable material which will vaporize at atemperature above normal operating temperature for the apparatus orenvironment and below that temperature at which partial destruction willoccur to the apparatus or in the environment as a result of heat. Thus avapor is created which can be sensed by an ionization detector prior tothe occurence of heat damage. The body upon which the vaporizablematerial is deposited comprises a machine or apparatus component whichis being monitored or alternatively the body comprises an independentsupport body provided for supporting the vaporizable material within theenvironment being monitored. In accordance with other features of theinvention, vaporizable materials having dif ferent temperatures ofvaporization are employed and are deposited on difierent bodies in orderto effect ionization detection which discriminates between apparatus orenvironments which are experiencing abnormal conditions.

These and other objects and features of the invention will becomeapparent with reference to the following specification and to thedrawings wherein:

FIG. 1A is a schematic diagram in block form of an apparatus utilizingan ionization detection system in accordance with the present invention;

FIG. 1B is a cross section of a portion of a motor of FIG. 1Aillustrating a vaporizable material deposited thereon;

FIG. 2A is a front elevation of a large scale electronic apparatushaving a detection system in accordance with this invention;

FIG. 2B is an enlarged view of a printed circuit board utilized with theapparatus of FIG. 2A;

FIG. 2C is an enlarged side view of a portion of the circuit board ofFIG. 2B and illustrating a vaporizable substance deposited thereon;

FIG. 3A is a side view of a support body in a vaporizable materialdeposited thereon;

FIG. 3B is a view taken along lines 3B3B of FIG. 3A; and,

FIG. 4 is a schematic diagram in block form illustrat ing a detectionsystem for detecting faults and discriminating between the source of thefaults.

Referring now to the drawings, and more particularly to FIG. 1A, thereis shown a motor generator combination comprising a motor 10 which ismechanically coupled to a generator 12. As is well known, a motor isoften subject to overheating and self-destruction. In accordance withthe invention, a film or layer 14 of a vaporizable material which can bedetected by an ionization detector is deposited upon a paint film 16which is formed on a motor cover 18. During operation, the motor willhave an elevated operating temperature with respect to its off-dutytemperature. This operating temperature T comprises its design safeoperating temperature. The material 14 is selected to at least partiallyvaporize at a temperature T which is intermediate the safe operatingtemperature T, and a higher temperature T which if attained duringoperation will result in serious damage and possible destruction of themotor 10. The attainment of a temperature T by the motor 7 representsthe existence of a faulty condition in a motor and the vaporization ofthe material 14 at this temperature results in an automaticallydetectable indication which can be utilized to interrupt power to themotor 10. The vapor emanating from the material 14 at the temperature Tis sensed by an ionization detector 20 which is positioned in proximityto the motor generator assembly and preferably adjacent to the motor 10.Ion ization detectors are well known and the details of the detector 20are therefore not illustrated. Ionization detector 20 is adapted tosense the existence of vapors emanating from the material 14. Thisrepresents the occurrence of a faulty condition and an output. from theionization detector which may comprise a voltage, a current or avariation in impedance is coupled to an amplifying means 22 whichcontrols a power interrupt circuit 24. Operating power for the motor 10is derived from an alternating current source 26 and is applied to themotor through the interrupt circuit 24. The interrupt circuit comprisesrelay coils or circuit breakers through which power is supplied to themotor and which provides for interruption of this coupling by theamplifier 22 upon sensing of the vapor by the ionization detector 20.Thus, the motor is prevented from selfdestruction through overheating bythe provision of a vaporizable material 14 which vaporizes at atemperature T which is above the desired operating temperature T of themotor and below a temperature T at which serious damage to the motorcould occur.

The vaporizable material 14 comprises a substance which providesvaporization at a desired temperature and which is compatible with thematerial to which it is applied. The material 14 may comprise any ofvarious materials including varnish, paste, paint, cement, enamel, paperor other organic materials, a polymer or the like. This material isselected, to exhibit vapor or fume or aerosol generating characteristicsat a desired temperature threshold. The coating material may be in theform of a liquid such as a varnish or a paint, in the form of a solidsuch as a resin, plastic, polymer, cement or in the form of a gas whichis absorbed by the body to be coated and released upon an increase intemperature.

FIG. 2 illustrates an electronic apparatus which advantageouslyincorporates the detection system of this invention. The electronicapparatus comprises a cabinet 30 having a plurality of slidable drawers32 which can be withdrawn from the cabinet to expose a large number ofprinted circuit boards 34 mounted in each drawer. A typical printedcircuit board 34 is illustrated in FIG. 28. There is mounted on theprinted circuit board 34 a plurality of electronic components such ascapacitors, inductors, and resistors. These elements are intercoupled onthe printed circuit board by printed wiring not illustrated. In order toprotect the electronic apparatus from overheating and self-destruction,the vaporizable material 14 is shown in FIG. 2C to be deposited upon theprinted circuit board 34. The material 14 may alternatively be depositedupon the electronic components and more particularly on those componentswhich perform an important operation in determining the characteristicsof operation of the circuit. Thus, when a critical oscillator circuit istemperature sensitive and a component thereof begins to overheat as aresult of a fault in the circuit itself or because of a defect of thecircuits or in the cabinet of the apparatus, then the operation of theapparatus can be deleteriously affected. The vaporizable film 14 canthen be desposited upon the elements of the oscillator circuit, forexample, in order to sense when the components of this circuit departfrom their operating temperatures and attain a temperature T at whichthe operation of circuit becomes unreliable.

While there has been illustrated in FIGS. 1 and 2 arrangements whereinthe vaporizable material may be deposited directly on the apparatus oron a circuit board or component as illustrated with respect to FIG. 2,at times it is desirable to monitor environmental conditions in an areasuch as a storage area wherein there is no suitable body upon which todeposit the vaporizable material. In this case, the material isdeposited upon a body 40 which as illustrated in FIG. 3A is shown tocomprise a cylindrically shaped, thin walled, metallic body 40 which ismounted on thermally insulating support members 42 and suspended aboutan axis thereof on support body 44. The vaporizable material may bedeposited about the outer surface of the drum shaped body 40 asillustrated in FIG. 3B. The body 40 may then be placed in those areaswhere it is desirable to monitor the atmospheric temperature forexample.

Two or more bodies or systems can be simultaneously monitored bydepositing difierent vaporizable materials on the bodies and byproviding ionization detectors which are adapted to sense the particularmaterial. In FIG. 4 there is illustrated a detection arrangement forsensing when either of the bodies 50 or 52 attain an undesired elevatedoperating temperature T and for detecting and indicating which of thebodies has attained this undesired condition. A film of vaporizablematerial 54 is deposited on an outer surface of the body 50 while a filmof different vaporizable material 56 is deposited on an outer surface ofthe body 52. An ionization detector 58 is provided and is adapted forsensing the occurrence of a vapor from the material 54 while anionization detector 60 is also provided and is adapted for sensing theoccurrence of a different vapor from the material 56. An output from theionization detector 58 is coupled, via an amplifier 62, to an indicatorcircuit 64 and to an interrupt circuit 66 for interrupting theapplication of power to the bodies 50 and 52. The indicator circuit 64comprises a display board along with suitable triggered electronicstorage elements such as flip-flop circuits which are triggered by asignal derived from the amplifier 62 and which energize and causeillumination of a lamp 68. Similarly, an output signal from the iondetector 60 is coupled via the amplifier 70 to the display panel 64 andto the interrupt circuit 66. While outputs from either the ionizationdetector 58 or 60 will cause interruption of power to both of thedevices, it is apparent that power can be interrupted to one of thedevices independent of the other device.

Upon detection of a fault, the ionization detector alternative todecoupling power from the device can provide an audible alarm or avisual alarm as indicated in FIG. 4. The ionization detecting device mayalso be remotely located and include a transmitting means fortransmitting to a receiving station. An arrangement of this type isdescribed and claimed in my co-pending U. S. patent application Ser. No.221,235, filed Jan. 27, 1972, and nt t es? ALARMSQTEM;

An improved method and apparatus for the ionization detection has thusbeen described. While the system has been described with particularattention to faulty conditions, it will be apparent that the techniqueemployed can also be utilized in processes for effecting control. Thedescribed invention is particularly advantageous in that partial damageor destruction of the apparatus is avoided while at the same timeselective monitoring and detection is effected for distinguishing andlocalizing a faulty condition. The system is operable fordetectingfumes, gases and aerosols which are emitted upon theestablishment of the predetermined condition. I

While there have been described particular embodiments of the invention,it will be apparent that various modifications may be made thereinwithout departing from the spirit of the invention and the scope of theappended claims.

What is claimed is: 1. An improved detection arrangement for sensing anelevation in temperature of a body from a temperature '1" to arelatively higher temperature T and for generating an indication of theelevation in temperature to the temperature T comprising:

a support body whose temperature is subject to rise; a materialpositioned on said support body in close contact with said body wherebythe temperature of said material will vary substantially in accordancewith variations in the temperature of said body, said material beingindependent of the structure of said body and adapted to emit into theatmosphere above the body at a predetermined elevated temperature T agaseous phase substance whose existence can be detected by ionizationdetection means; ionization detection means positioned near said supportbody for detecting an emission into the atmosphere about the body fromsaid material; means responsive to said ionization detector forproviding an indication of the detection of said substance, said supportbody comprising a member of an energized apparatus, a source of energy,means for applying energy from said source to said apparatus, said meansfor applying energy adapted to be responsive to the electricalindication of said ionization detector for automatically interruptingthe application of energy to said apparatus upon an occurrence of saidindication.

2. The apparatus of claim 1 wherein said apparatus comprises anelectrically energized apparatus, said source of energy comprises asource of electrical energy and said means for applying electricalenergy to said apparatus comprises electrically responsive means whichare responsive to said indication for interrupting the application forenergy to said apparatus.

3. The apparatus of claim 1 including a second support body, a secondmaterial deposited on said second support body and adapted for emittinga gaseous phase substance at a predetermined temperature, a secondionization detection means for detecting and providing an electricalindication of the occurrence of an emission from said second materialand means responsive to said electrical indication from said secondionization detector providing an indication of the emission from saidmaterial.

1. An improved detection arrangement for sensing an elevation intemperature of a body from a temperature T1 to a relatively highertemperature T2 and for generating an indication of the elevation intemperature to the temperature T2 comprising: a support body whosetemperature is subject to rise; a material positioned on said supportbody in close contact with said body whereby the temperature of saidmaterial will vary substantially in accordance with variations in thetemperature of said body, said material being independent of thestructure of said body and adapted to emit into the atmosphere above thebody at a predetermined elevated temperature T2 a gaseous phasesubstance whose existence can be detected by ionization detection means;ionization detection means positioned near said support body fordetecting an emission into the atmosphere about the body from saidmaterial; means responsive to said ionization detector for providing anindication of the detection of said substance, said support bodycomprising a member of an energized apparatus, a source of energy, meansfor applying energy from said source to said apparatus, said means forapplying energY adapted to be responsive to the electrical indication ofsaid ionization detector for automatically interrupting the applicationof energy to said apparatus upon an occurrence of said indication. 2.The apparatus of claim 1 wherein said apparatus comprises anelectrically energized apparatus, said source of energy comprises asource of electrical energy and said means for applying electricalenergy to said apparatus comprises electrically responsive means whichare responsive to said indication for interrupting the application forenergy to said apparatus.
 3. The apparatus of claim 1 including a secondsupport body, a second material deposited on said second support bodyand adapted for emitting a gaseous phase substance at a predeterminedtemperature, a second ionization detection means for detecting andproviding an electrical indication of the occurrence of an emission fromsaid second material and means responsive to said electrical indicationfrom said second ionization detector providing an indication of theemission from said material.